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H. DUNSMUIR. MULTIPLE EXPANSION ENGINE.

' No. 449,284. Patented Mar. 31,1891.

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H. DUNSMUIR. MULTIPLE EXPANSION ENGINE.

No. 449,284; Patented Mar. 31, 1 91.

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H. DUNSMUIB. MULTIPLE EXPANSION ENGINE.

No. 449,284. Patented Mar. 31, 1891.

J L J UNITED STATES PATENT OFFICE.

HUGH DUNSMUIR, OF GOVAN, SCOTLAND.

MULTIPLE EXPANSION-ENGINE.

SPECIFICATION forming part of Letters Patent No. 449,284, dated March 31, 1891. pp i t n file eptember 25, 1889. $erial No. 325,104. (No model.) Patented in England July 2, 1889, No. 10,665.

To all whom, it may concern:

Be it known that I, HUGH DUNSMUIR, engineer, of the firm of Dunsmuir & Jackson, Govan Engine WVorks, Govan, in the county of Lanark, Scotland, have invented new and useful Improvements in the Arrangement of Multiple Expansion-Engines for Screw-Propulsion, (which has not been patented in any country except Great Britain by Letters Patent dated July 2, 1889, No. 10,665,) and I do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in the manufacture or art to which it relates to make and use the same.

This invention relates to the arrangement of multiple expansion-engines for screw-propulsion; and it consistsin placing triple, quadruple, or compound engines athwartships and connecting the high-pressure, intermediate, and low-pressu re cylinders to separate crankshafts, or to the propeller shaft or shafts of a single screw or of twin-screw or multiple-screw steamers, and connecting the several shafts so actuated by means of a plurality of cranks and connecting rods, as hereinafter more particularly set forth, so that while the use of separate sets of engines for the several propeller-shafts is obviated the economy and other advantages resulting from the employment of triple or other multiple expansionengines may be obtained.

It should be understood that I do not claim, broadly, any means of whatevercharacter for connecting such shafts, my invention consisting in an improved combination of parts, resulting in greater simplicity and economy of construction and efficiency of operation.

In the accompanying drawings, which illustrate my invention, Figures 1 and 2 are respectively an elevation and plan showing triple expansion-engines arranged and geared to drive a single propeller-shaft. Figs. 3 and 4 are similar views of triple expansion-engines as applied for driving twin-screw shafts; and Figs. 5 and 6, the same arrangement of engines applied to drive three propeller-shafts. Figs. 7 and 8 represent a set of quadruple expansion tandem engines arranged to drive two propeller-shafts. Figs. 9 and 10 show an arrangement of quadruple expansion-engines driving four propeller-shafts; and Figs, 11 and 12 show two cylinder compound engines geared to drive twin screw-shafts.

In adapting triple expansion-engines to operate the propeller-shaft in a single screwstea-mer, as represented at Figs. 1 and 2, the intermediate and low-pressure cylinders A and A are directly connected each to a crank B on a short shaft 0, while the high-pressure cylinder A is connected to a crank on the propeller-shaft D; or the arrangement may be varied. The two side crank-shafts O and the propeller shaft D are connected together either by cranks or disks and differently-situated crank-pins D D and connecting-rods E E, which are provided in pairs, as shown, to insure rotation of the several shafts in the same direction.

In adapting triple expansion-engines to operate the propellershafts in a twin-screw steamer, as represented at Figs. 3 and 4, the high-pressure and low-pressure cylinders A and A are directly connected each to one of the crank or propeller shafts D,while the intermediate cylinder is connected to a separate crank-shaft O, or the arrangement may be varied; and in order that the power and speed of rotation of the two propeller-shafts may be equalized and economical working insured the three crank-s11 afts are connected together, as shown, by cranks or disks and connectingrods.

In the case of twin screws driven by two cylinder compound engines, as represented at Figs. 11 and 12, one cylinder is placed directly over and connected to each shaft, the two propeller shafts being connected by cranks and connecting-rods, as shown, and when quadruple engines are employed to drive twin screws, as represented at Figs. 7 and 8, the first and third cylinders A A of the series may be placed tandemwise over the second and fourth cylinders A A the propellershafts being connected as before described.

When three screws and propeller-shafts are employed, as shown at Figs. 5 and 6, the cyl inders of a triple expansion-engine are directly connected one to each propeller-shaft, the shafts being connected by cranks, as before described, and for four screws quadruple engines, as represented at Figs. 9 and 10, are

used, the cylinders of the series being connected each to the propeller-shaft directly under it, While the several crank-shafts are in like manner connected together.

The improvements hereinbefore described are to be distinguished from constructions wherein it has been proposed to secure the uniform rotation of two shafts by means of a single connecting-rod and frictiongear, in which construction there is not such positive connection between the two shafts as to obviate all possibility of slipping and of the counter-revolution of one of the shafts. According to my improvements there is no possibility of the two (or more) shafts or of the engines operating the same losing their absolute unity of motion, and the main cranks are each helped over the dead-points by power transmitted from the adjoining shaft or shafts with absolute certainty.

Having now described my invention, What I desire to claim, and secure by Letters Patent, is

1. In a multiple expansion-engine for screwpropulsion, the combination of a series of cylinders, the main screw-shaft, one or more separate shafts 0, making with the main shaft a shaft for each cylinder, a crank on each shaft, a pitman-connection between the piston of each cylinder and its crank, crank-pins D,

connected with and carried by said shafts, other differently-situated crank-pins D also carried by the shafts, and connecting-rods E E, joining said pins, substantially as set forth.

2. In a multiple expansion-engine for twinscrew propulsion, the combination of two cyl inders, shafts and main cranks set at different angles with which the pitmen of said cylinders are connected, an intermediate shaft and main crank set at a different angle from the first-mentioned cranks, a third intermediate cylinder having its pitman connected with the latter crank and the double connecting-rods E E, and corresponding auxiliary cranks set at an angle to each other, and wristpins by which said intermediate shaft is connected with the other shafts, substantially as set forth.

In witness whereof I have hereunto set my hand and seal this 24th day of August, 1889.

HUGH DUNSMUIR. [n s.] 

